Newsletter Issue 01 June 2013 - absanz

Air-tightness testing of high level containment facilities: regulatory necessity
or simply nice to know?
Gordon McGurk Ph.D.
gordonmcgurk@aapt.net.au
This article is a summary of a presentation from the 2012 ABSANZ conference
T
he majority of guidelines and standards that are
applicable to the construction or design of biocontainment
facilities in Australia contain either
guidance on, or relate to, a requirement around
the air-tightness of the facility. However, given the way
in which high-level containment facilities operate, by
maintaining the facility at negative pressure, the rationale
for this requirement is uncertain. Does it relate to
containment of micro-organisms, or is it more about the
ability to decontaminate the facility following the use of
the microorganisms without jeopardising the health and
safety of personnel outside the facility?
From a regulatory perspective, there was a lack of airtightness
information available with respect to facilities
currently in operation. Therefore, in order to address the
information gap regarding the air-tightness of PC3 biocontainment
facilities, and perhaps provide evidence to
support any relevant regulatory change, a project to
quantify the structural and seal integrity of laboratory and
small animal PC3 containment facilities by means of an
air-tightness test was conducted. Air-tightness was
measured by calculating the amount of air leaking from
the facility when pressurised to a positive pressure of
200Pa over a 20 minute period.
Of the 20 facilities tested 10 had an air-leakage rate
which was within or better than the range (120 L/min.-
1200 L/min.) advised for PC3 level containment facilities
in Part 3 of the Australian and New Zealand Standard for
Safety in Laboratories (AS/NZS 2243.3 [2010]).
A further 8 facilities had an air-leakage rate of
approximately 1400 L/min. or more. The remaining two
facilities were unable to be measured due to structural
issues.
The results of this testing indicated that the air-tightness
of facilities varies due to the combination of a number of
factors including age of the facility, construction method,
and number of penetrations through the containment
barrier.
In general, air-tightness decreased with the increasing
age of the facility, with the most recently constructed
facilities having air-leakage rates of